Heating device and combustion process



R. J. WALLER Filed 1946 DEVICE AND COMBUSTION PROCESS s Sheets 1 \& M7;

INVENTOR. AD/(H/IIFO J 1 ER Dec. 12, 1950 R. J. WALLER m'r'mc DEVICE AND comaus'rxou PROCESS 3 Sheets-Sheet 2 Filed Aug. 17, 1946 I I r I Ila/$17114 Ill/I Emmi",

R/c/mRa J WALLER W i ATTOlP/VEPS Dec. 12, 1950 R. J. WALLER 2,533,647

HEATING DEVICE AND COMBUSTION PROCESS 3 Sheets-Sheet 3 Filed Aug. 17, 1946 INVENTOR. Amz/A/w f h/HLLE/P Patented Dec. 12, 1950 HEATING DEVICE AND COMBUSTION PROCESS Richard J. Waller, Bridgeport, Conn.

Application August 17, 1946, Serial No. 691,270

11 Claims. 1

This invention relates to heating devices, and more particularly to devices designed especially for the use of liquid fuels. It is a continuationin-part of my copending application Serial No. 564,851 filed November 23, 1944, now Patent 2,497,282, Feb. 14, 1950.

An object of the invention is to provide a simple type of heating device that will burn liquid fuels very efficiently.

Another object of the invention is to provide a device of this character that is adapted particularly to utilize the industrial fuel oils.

A further object of this invention is to provide means for elfecting substantially complete gasification of such fuel oils prior to their combustion.

Complete gasification is an essential requirement for ultra high efficiency of operation. When the industrial fuel oils are used the problems of securing such gasification are of greater complexity than with lighter fuels which flow readily and vaporize easily. It has been found advantageous to preheat the industrial fuel oils prior to their gasification. An object of this invention is to provide novel means for effecting such preheating which is embodied in the device itself, thereby eliminating the necessity for extra equipment.

The complete gasification of the fuel when spoken of in this specification and its claims means the production of homogeneous gaseous mixtures for combustion whose Original components of fuel and air or other oxygen-containing gas are so blended or merged, that the fuel will not thereafter separate from such gaseous mixtures by liquefaction at moderate temperatures, and furthermore, that the fuel and oxygen-containing gas in the homogeneous gaseous mixtures are in the proper proportions for complete combustion in the absence of additional oxygen or oxygen-containing gas.

In effecting this gasification, in general, the liquid fuel is preheated and delivered under slight pressure and in vaporized condition through a nozzle located in proximity to a nozzle delivering air or other oxygen-containing gas hereinafter called entraining gas. This entraining gas entrains the fuel vapor, serving further to break up or atomize the vapor particles. Additional air or oxygen-containing gas hereinafter termed processing gas is delivered in the region of the nozzles and the entrained vapor, entraining gas and processing gas are delivered to expanding zones, the first of which is divergent and the next succeeding of which is larger in section than the largest section of the divergent zone. In this second zone, the complete gasification occurs producing the desired gaseous mixtures for combustion which pass out of the said second zone through a burner nozzle and are burned externally of the second zone in a refractory shell which surrounds the burner nozzle. The refractory shell becomes incandescent. Part of its heat is radiated rearwardly and some of the hot products of combustion are circulated rearwardly of the shell, for fuel preheating purposes and for the purpose of heating portions of the expansion zones. The preheating of the fuel is effected by providing a preheating chamber so positioned as to receive heat radiated backwardly from the shell and also from rearwardly circulating hot prodnets of combustion. In addition, the preheating chamber may further be heated electrically. Suitable ignition means also are provided.

A further object of the invention is to provide structure capable of operating as just described.

To the accomplishment of the foregoing and such other objects as may hereinafter appear, this invention consists in the novel construction and arrangement of parts hereinafter to be described and then sought to be defined in the appended claims, reference being had to the accompanying drawing forming a part hereof, which shows merely for the purposes of illustrative disclosure, preferred embodiments of the invention, it being expressly understood, however, that changes may be made in practice within the scope of the claims without digressing from the inventive idea.

In the drawing in which similar reference characters denote corresponding parts:

Fig. 1 is an elevational view of one form of the device;

Fig. 2 is an end elevation viewed from the right-hand side of Fig. 1;

Fig. 2a is a fragmentary section taken along line Za-Za of Fig. 1;

Fig. 3 is a longitudinal section of the device of Figs. 1 and 2 taken along line 33 of Fig. 2 and viewed in the direction of the arrows;

Fig. 4 is a longitudinal section taken along line 4-4 of Fig. 4a and viewed in the direction of the arrows;

Fig. 4a is an end view taken along line 4(l4a of Fig. 3 and viewed in the direction of the arrows;

Fig. 5 is a longitudinal section of a modified form of devicetaken along line 5-45 of Fig. 6 and viewed in the direction of the arrows;

Fig. 6 is an end elevation viewed from the right of Fig. 5;

Fig. 7 is a longitudinal section taken along line 'i'l of Fig. 6; and

Fig. 8 is a fragmentary section illustrating a modified means for feeding fuel to the preheating chambers of either of the devices of Fig. l or 5.

Referring to the drawing, and first to Figs. 1-4 inclusive, the heating device E comprises generally blender parts A and B wherein a fuel previously preheated as will be presently described is entrained with entraining air or other oxygen-containing gas, and treated with additional processing air or other oxygen-containing gas, an expansion chamber '0 connected with the blender parts by a diverging tubular portion D into which the fuel and gas mixture is discharged from the blender parts, an adjustable burner nozzle E, refractory-material in the form of a cup or shell F arranged in conjunction with the burner nozzle E, a fuel preheating chamber G, and means for preheating such chamber all for purposes to be presently described.

The blender part A includes a casting it! of suitable metal such as brass or the like. This casting It has a passage ll extending longitudinally thereof and terminating at one end in a nozzle I2. The casting It has an enlarged recess l3 at one end into which the opposite end of passageway H opens. A tube or conduit I4 is secured in the recess i3 and connected to a source P of air or other oxygen-containing gas supply. A second passageway extends longitudinally of the casting Ii). This'passageway l5 terminates at one end in recess It so that it communicates directly with the tube or conduit M. The opposite end of the casting it has a recess it and the other end of passageway l5 terminates in this recess IS. A suitable springactuated Valve i? that is movable transversely of the passageway i5 serves to control the how of gas from the supply source P through the passageway i5. This Valve I! normally rests upon a seat It closing off passageway l5. A

pivoted cam lever i9 serves to raise the valvei'l from its seat l8 against the action of a spring 19a so that the valve I? may be 'moved to open passageway I5 to any extent desiredfor apurpose presently to be described.

The blender part B comprises a tubular part 20 preferably of the same material as part IE3. This part 2% is dimensioned to fit withinthe recess 16 of the part It and is secured in' place as by welding or in other suitable ways. The bore of this part 29 is sub-divided into a cylindrical section 2!, an inwardly tapering section 22, a second cylindrical section 23 of reduced di-' ameter and a flaring section 24. The latter three sections resemble a Venturi arrangement. A shoulder 26 is defined between the larger cylindrical section 2| and the tapering section 22.

The nozzle 12 projects from the casting It into the cylindrical bore portion 23 of the blender part B. An annular flange-27 on the nozzle [2 is positioned to abut the shoulder 26. This flange has a plurality of distributing ports or orifices 28.

The portion of bore 2| betweenthe outlet end of passageway I5 and the flange Z'i constitutes a distributing chamber for processing air or other oxygen-containing gas flowing thereto through passageway i5. erably are uniformly distributed relative to the nozzle 42 for a purpose presently to be described. There may be six' or more such ports, for example.

The ports or orifices 2t, prefatomizing'eifect for purposes presently to'b'e deberf-l il to provide leak proof joints 39, 49.

ber D and is secured as by the nut 3| to the blender part B. The divergent tubular chamber D terminates in a substantially cylindrical expansion chamber C having an end plate or wall or deflection surface 35. This end wall is substantially a plane surface except at its center for a purpose presently to be described. A tubular extension 36 extends forwardly of the surface '35, being of substantially smaller diameter than and opening into the chamber'C through the wall 35. This tubular extension is centrally located. It is threaded internally to receive parts of the burner-nozzle E.

purposes 'to be presently described. The shell 33 is spaced from the wall 35 for purposes to be presently des'cribed'and'the traversing tubes '4! extend rearwardly from 'the shell into the space betweenthe shell 38 and'the said wall 35.

Fuel is delivered to the preheatingchamber G. To this end a fuel tube -46 and a surrounding jacket tube 47 extend into the chamber G through a wall of the shell 38. The 'jack'eting tube 3'! is of larger diameter than-thefuel tube 46; providing a gas passageway 49 that surrounds the fuel tube 46. The fuel'tube 48 is connected in the passage of a coupling member 5%. A conduit 5! leads from the latter to a fuel source The jacketing tube 41 is 'connected'to a coupling part 52 from which a conduit 53 leads either-to the same air or oxygen-containing gas source P that delivers similar gas to the supply duct 14, or it may beconnectedto an independent source. It is to be understood-that suitable control valves 54, 55 are provided somewhere in the conduits M553 leading to therespective coupling members or partsEt and 52.

The outlet 53 of the-preheating chamber G is connected by a conduit-5d to a nozzle 'fiil'which terminates-in there'gion" of air or other oxygencontaining gas nozzle i Z-as will be presentlynescribed. The two nozzles i2 and 66 are disposed relative'to each 'other'sothat flow 0f"entraining gas from the nozzle '12 has'an entrainin'g'iand scribed. The conduit '59 passes through the chambers C andD.

A preheater To isprovide'd. This Jpre'heater comprises a block 'il'of insulating and heat-resisting material-such as porcelain. "An electrical heating coiliZis supported in a'groovels in the block'and lies below the surface of the said groove. The block has holes "it extending through it in this-groovelfi. The block il 1s "positioned and supported suitably on'the'tubular member 3% with the heatingcoil exposed toward thes-hell-38 and 'in close proximity to the wall 38a of the latter so that heat radia'ted-"fro'mthe coil 72 will warmthe preheating' chamber 38' by heating of its wail 38a. The terminals of the coilare connected to leadsm, 75 which maybe connected 'to a source of e1eetr ica1 power. The *block is supported'suitably from casing G as'at 79.

The bottom 'F'a' of the refractory cup or shell I has the overhanging flange or skirt"Fb-,-\ l1ich latterjwhe'n in abutment with the f ace- 3 8b er 'the preheating shell 38, defines a chambe'r or recess 8c. The tubes open into the chanibe r tilfor The tubular part 30 has the divergent cham-. -75'a purpose presently to'be described. The'shell F is secured in place, for example, by the threaded sleeve 8|. This sleeve extends through an opening 82 in the shell bottom Fa, the sleeve 81 being headed at Bia so that it may be tightened after threading into the tubular member 35. The sleeve 8 l is internally threaded to receive a tubular threaded portion 83 of the burner tip E. Passageways 84 in the tubular portion 83 of the tip E and grooves are provided. The grooves 85 and the outer end of the sleeve 8| define passageways 88 of adjustable dimensions for egress of the combustible product from chamber C.

The bottom Fa of the shell has a recess or groove 38 to receive an electrical heating coil 90. This coil 9c is suitably supported in the recess and its terminals are connected to electrical leads iii, 92 which may be connected to a source of electrical power. This coil 90 functions primarily as an igniter as will be presently described.

Ports or passages 95 are provided which extend through the bottom Fa of the refractory shell F from one face to the other thereof. These passages are so positioned, as seen in Fig. 2 that parts of the starting or igniting coil 93 are visible therethrough for purposes presently to be described. These ports or passages 95 terminate on the outer face of the bottom Pa in the region of curvature 96 so that ledges or shoulders 9'! (Fig. 3) are provided that lie in the path of combustible gases emitted from the passageways 85, so that a portion of such gases are deflected through the ports or passages 95 into the chamber 88 and into contact with the starting or ignition coil 9i for ignition purposes. When ignition has been established and the starting coil turned off, hot burning gases and hot products of combustion are deflected by the shoulders 97 into the chamber 89. Such burning gases or products of combustion circulate in this chamber 85) and heat the wall 381) of the preheating chamber G and some also pass through the tubes 4! providing further heat for the preheating chamber G. The gases emerging from tubes 4! are still hot and strike the end plate 35 of the expansion chamber C serving to heat the latter all for purposes presently to be described.

In operation of the device, the preheating coil 22 is connected to electric power so as to heat the preheating chamber G. The fuel valve 54 is opened so that fuel starts to flow into the preheater chamber G. The heat generated by the preheating coil i2, reduces the viscosity of the fuel delivered to the preheating chamber G and at the same time begins to vaporize it. The valve 55 is opened admitting air to the chamber G which mixes with the fuel therein to form a vapor that is a preheated mixture of fuel and air or other oxygen-containing gas. The air or other oxygen-containing gas admitted to preheater chamber G is regulated by valve 55 so that the said vapor under suificient pressure is developed to force its delivery from the preheating and vaporizing chamber G through the conduit 59 to the vapor nozzle 6!}. This air is important because its presence increases the CO2 content in the gaseous products at the burner. As the vapor emerges from the vapor nozzle 6t, it meets with additional air or other oxygen-containing gas delivered by nozzle 42. This additional gas, which will hereinafter be referred to as entraining gas, entrains such vapor, atomizes any droplets in such vapor and moves with the entrained vapor first into the divergent chamber D, then into the cylindrical expansion chamber C and finally outwardly of the latter through tubular member 36, tube 83, passageways 84 and passageways 86. During such movement, the vapor and entraining gas become intimately mixed to form a combustible gas mixture which is that emerging from the passageways 86. This combustible mixture is directed so that part of it strikes the shoulders 91 and is deflected through ports or passages into contact with the ignition coil at. When the latter has its leads 9!, e2 connected to a power source, it becomes incandescent and ignites the combustible mixture. This ignition spreads backwardly through the ports or passages 95 to the combustible mixture emerging from passageways 86. Once such combustion has been established and the refractory shell F has become incandescent, the ignition coil 96 may be disconnected. Preheating coil 12 likewise may be disconnected after combustion has. been started and operating temperatures have been reached. Provision not constituting part of the invention, may be made for the automatic energization and deenergization of the ignition coil as and of preheating coil 72.

The combustible mixture emerging at the burner nozzle E, so far described, may be described as rich because the amount of fuel therein relative to the air or other oxygen-containing gas in it is at a maximum. Once combustion has been established, the richness of this mixture can be reduced. This is accomplished by opening the valve i? to the desired degree so that air or other oxygen-containing gas flows into distributing chamber 2i and from there through the ports 28 about the nozzle l2. This latter gas is conveniently referred to hereinafter as processing gas. The opening of the valve I? to permit this processing gas to flow automatically reduces the vapor entrained by the entraining gas coming from nozzle l2, and thus the richness of the fuel gas mixture delivered to the chambers C and D as previously described. The processing gas is delivered through the ports 28 so that in the region of entrainment at the tips of nozzles I2 and 68 it is in the form substantially of an envelope. As the entraining gas, the entrained vapor and the enveloping processing air move through divergent chamber C and into expansion chamber D, intermixing commences which results eventually under operating conditions in complete homogenization of the vapor and air or other oxygen-containing gas so that the combustible product emerging from the passageways 86 at the burner E is homogeneous and completely gasified for utmost efiiciency of combustion. Tests of such product show that the homogenization is substantially complete because fuel does not separate by liquefaction from samples of such product even at room temperature or lower. Combustion is complete even in the absence of additional oxygen or oxygen-containing gas at the burner E.

The burning of the combustible products externally of the expansion chamber C and primarily in the refractory cup F is a feature of the invention. This burning causes the refractory to become incandescent so that combustion will be maintained even after the starting coil tie is disconnected from power. In order to maintain this incandescence, it will be understood that the velocity of the gasified combustible products emerging from passageways 85 must be maintained at a level necessary to maintain the required incandescence for perpetuation of com- 7 termined by. the'orifiee passages 85.. These" in turn: may be: variedi in: the embodiment shown by adjustment of the; irn the: threaded sleeve 8|. otherr' suitable adjustment may be. provided,

During operation, the experienced-operatonwill find that optimumgasificationis obtained when a determined volume ratio is maintained between the entraining gas coming fromvnozzle l2: and the processing gas. This. volume ratiowill vary depending: upon. initial. pressure conditions from the air. or" other oxygenecontaming supply source P and the naturemfthe fuelxused. The adjustability of: the. valve ll permits: variation ofthe-ratio2to meet difierent conditions; However, with. any device. embodying-the? invention, if it is designed; to operate. under a standard. set oi? conditions, the: valve: Iii needdoe adjusted but once so that itcan always be'openedto that position necessary. to create the; proper: determined ratio. between the: entrainingzgas and the-processing gas. Test data. indicate that-the best results are obtained inioperatio when the relationship between the volume of entraining gas and'ther'processinggasis of theorder oi-Aibto 60. g-

Anfurtherrimportanttaspect oft-he invention is thatsuccessfulioperationiand-maximum efficiency depends upon maintenance of an elevated temperature at the end palte or wall 35 of chamber C. I.-his"wall or defi'e'cting suriace ma-y be termed a: hot plate. If the heatedlproducts' of combusticn: emerging from the tubes it have temperatures in excess of 1'100'F., then the hot plate 35: will bei suificiently heated.

It: will be understood; of course, thatthe wall or hot plate 35. is part of the. metallic heat conductive-material whose walls definetheexpansion chamber C. and 1 the divergent. chamber 12 so that thesewallsimturn become 'warmed by heat conduction; The" hottest region', of course, is in the-neighborhood of the"ht plate If the parts have substantially the proportions shown, the maintenance of the hot plate 35 at its 7 required: elevated temperature: range, insures adequacy of warming. of the walls defining the chambers G and D sorthat complete gasification of the fuel with air-or other oxygen-con:- taininggas occurs before the combustion product emerges from the burner OiifiCGSB'fi:

Another imp ortantaspect of the invention lies inproviding-means to prevent the gasesdefie'cted by the hot plate 35 from movingback" from the expansion. chamber C into cooler portions of the: divergent :chamber D. It willbe notedftha't the expansion chamber-G increases'abruptly in diameter relative to the largest diameter? of the diverging portion D; The'shoulder we thus providediunctionsto prevent the reentry of. the gasesideflected. by the hot plate? 35-:into cooler portions of the divergentchamber D, servingas a deflector means.

It is. well known that when a" fluidh-itsa' hard surface with considerable Velocity in'a" direction generallyperpendicular to. the surface;- the fluid spreads .out in all directionsin a thin sheet If the :surface is turned :back-asin a cup or a glass; the fluid, Water for: example; strikes the bottom' inside of the.glass;,turns and follows along; the surfaceof the sidesand comes out of the glass inacylindrical-sheet.

The conditions-inithe chambers C and D. now considered.

The main fluid stream R ccmprisin the vapor. product emerging from nozzle and entraining air. or: other oxygen-containing gas: from the nozzle= l2 and the processing: gas impinges on the portion of the hotvpla'te 35 in the. region-sur roundingjthe orifice: of the tubularzmemb'er 36 in a? direction moreorless perpendicular to thei said plate and is deflected. Thedeflected stream spreads-in a thin sheet'radiall inall' directions toward thewallsof the chamber'C as denotediby the a'r-rows S. Then,.in turn, the"multiplicityof streams still deno'tedby arrows S formed by the radial dispersion.- turn andlfol'low the inner surfaceofthechamberc back-away.v from the hot plate 35;.untilthey encounter the-shoulder 'lfiil. The latterv deflects themi'inwardly toward the oncoming stream E. This strearrn R has consider"- able velocity and: dragsstreams deflected inwa'rd 1y byshoulder liitl back towards the hot plate 35. This completes: one round of the circulation cycle and turbulence results In the course of this circulation, streams denoted by arrows" S-ha've picke'd up heatiby' scrubbingithe hot plate and inner?v surfaces of the" hottest portions of. the chamber 0 adjacent to-said hot? plate? They, too, pick up someheat from the conduit: 59'. When they meet-the oncomin stream R they impart someloiitheir heat to it, thuspreheating it beforerit reaches the hot plate 3-5;

A" given p'ortionof thestream B; may complete a considerable number of cycles of circulation as Streams S before passing out through tubular member 36' and the passageways 86 Some portions ofstream R'even may-pass out'directly but these portions willbe small 'an'dn'egligiblel The preheating inthe chamber G further reduces the probability thatsuch portions are not completely gasified. As the conduit 59', the hot plate 35 and adjacent side walls of the chamber C increase in temperature and approach their stable ele-' vated' operating temperatures, more and more heat" is carried by the circulating: currents or streams. denoted by arrows S to the oncoming stream R'so that under actual operating conditions substantially complete honiogeneiz'ation occurs in this oncomingstream': R even before it reaches the hotplate 351. All or substantially all of the combustible product under operating conditions emerging from the passageways thus is substantially. homogeneousand complete- 1y gasified. It is thus'seen that the deflection shoulder we is apparently of importance, be cause. it assists in creating. turbulence among other things; The deflection'plate Sit-also; assigts'in creating turbulence.

The orifices or the nozzles I2 and 6t should be in proper relationship for greatest stability of op eration and optimum of' efficiency of operation. A: principal requirement is" that the respective nozzle orifice axes should? be co-planar and cross eachother substantially at right anglesand be substantially: in the positions .shown in the drawlugs.-

A modified form'of construction is' shown in Figs. 5-7 inclusive; Therein, .thetube 46' and it's jacketing tube 47' are'mounted "at an angle. The tubes 61'? and 41 0fFigS'. 1 4 inclusive mayrbe simi larlydisposed' if desired.

In Figs. 5-7 inclusive all parts bearing primed reference characters correspond with partswhich are similarly designatedibut un'primed in- Figs: 1-4--inc1usive.

It'will be notedithat'th'e tubular member '36" of Figs;* 5-7 is'shorter'th'anthe corresponding tubular membert' iof Figs. liiuclusive. Likewise, the vaporizi-ngz-chamber G defined'lbythe casing 38 isdirectly; adjacent the"hot" plate 35 instead of being spaced.- therefrom as-in' Figs; 1-4

inclusive. The refractory cup or shell F is secured to tubular member 36 in the same way as is shell F of Figs. 14 inclusive by parts of the burner E. A tubular member I jackets the shell F and extends rearwardly thereof to abut wall 35 and thereby permits tightening of the cup or shell F in place. The ports 95 of the refractory shell permit radiation of heat and flow of burning gases of combustion backwardly therethrough into space 80' against and about the walls of the casing 38' and also against and into contact with portions of the hot plate 35. The ignition coil 90' functions identically as that of Figs. 1-4 inclusive. If desired, this coil can be maintained in energized state until the device reaches its normal operating state. Durin this time its heat will radiate backwardly to aid in maintaining the necessary temperature of the preheating or vaporizing chamber G. When the operating state is reached, the heat from shell F is sufficient to maintain chamber G at its necessary temperature. In the alternative, some other conventional preheater arrangement may be provided for heating the preheating chamber G.

The principles of operation of the device of Figs. 5-7 are substantially identical with that of the form shown in Figs. 1-4 inclusive.

The couplings 50, 50', 52, 52 and tubes 46, 46', 41, 41' provided in the modifications of Figs. 1-7 inclusive for feeding fuel and air from conduits 5| and 53 either to chambers 38 or 38' may be eliminated if desired and the valve controlled conduits 5| and 53 coupled directly and independently to either the chamber 38 or 30 as shown in Fig. 8. In the latter, the chamber 38 has inlet nipples 806, ID! to which the respective valve controlled fuel feed line El" and air feed line 53 are connected. Operation with such connections is the same as that already described.

In all modifications it will be seen, all parts are compactly arranged and coordinated so that part of the heat of combustion is efficiently used for preheating purposes enabling practicable use of the devices with commercial grades of fuels. The parts are so arranged that, when the device is being operated under required operating conditions, complete homogeneization of the fuel with air or other oxygen-containing gas occurs. In other words, the combustible product emitted at the burner under such conditions is one in which no tendency to liquefaction of the fuel content exists at usual room temperatures or higher and wherein the combustible product is a gaseous homogeneous mixture of fuel vapor and oxygencontaining gas in the roper proportions for complete combustion in the absence of additional oxygen or oxygen-containing gas.

When the devices described are operating under design conditions the following conditions should exist:

Grade of fuel#2 fuel oil Rate of fuel supply7.5 c. c. per minute Pressure of gas supply from source P-G inches of H Ratio of volumes of entraining gas to processing gas1 cu. ft. per minute to 1.5 cu. ft. per minute, i. e. 40/60 Wattage of preheating coil T2 or coil 90 at 115 volts-300 watts Temperature of coils 12 or 90--about 1200 F.

Temperature of preheating chambers G or G- Temperature of hot plate 351100 F.

35-1000 F. Temperature of refractory2300 F.

These conditions may vary within a reasonable range depending upon the grade of fuel and air pressures used.

The devices shown have a rating of 15,000 B. t. u. per hour. There is no intention of limitation to such a rating. Devices of larger or smaller ratings may be manufactured simply by maintaining the proportionate dimensions of the various parts shown herein.

While specific embodiments have been shown, variations in structural detail are possible within the scope of the claims and are contemplated. There is no intention, therefore, of limitation to the exact details shown and described.

What is claimed is:

1. In a device of the character described, means for preheating liquid fuel to provide a fuel vapor, means for delivering liquid fuel to said preheating means, a nozzle means for delivering the vapor to'said nozzle, a second nozzle in proximity to the first-named nozzle, means for delivering entraining gas through said second nozzle, means for delivering processing gas as an envelope in the region of said nozzles, a tubular member having a diverging chamber into which the mixture of vapor, entraining gas and processing gas is delivered, and an expansion chamber directly adjacent said diverging chamber into which said mixture flows directly from said diverging chamber, burner means, a conduit arranged in a wall of said expansion chamber and communicating with said burner means, and a refractory shell arranged adjacent the said burner means, said shell having openings for delivering part of the heat of combustion rearwardly toward said wall.

2. In a device of the character described, means for preheating liquid fuel to provide a fuel vapor, means for delivering liquid fuel to said preheating means, a nozzle, means for delivering the vapor to said nozzle under pressure, a second nozzle in proximity to said first-named nozzle, means for delivering entraining gas through said second nozzle, the two nozzles being disposed so that the entraining gas moving past the vapor nozzle will entrain said vapor, means for delivering processing gas in the region of said nozzles, a tubular member having a diverging chamber into which the vapor, entraining gas and processing gas are delivered as a mixture, and an expansion chamber directly adjacent said diverging chamber into which the mixture flows directly from said diverging chamber, walls of said expansion chamber defining deflecting surfaces for effecting turbulence of the mixture flowing to said expansion chamber from said diverging chamber, burner means, a conduit arranged in a wall of said expansion chamber and communicating with said burner means, a refractory shell arranged adjacent the said burner means, said shell having openings for delivering part of the heat developed as a result of combustion rearwardly toward said expansion chamber, said means for preheating said liquid fuel being positioned intermediate said shell and said expansion chamber.

3. In a device of the character described, a casing defining a preheating chamber for liquid fuel, means for delivering liquid fuel to said chamber, electrical means for vaporizing liquid fuel in said chamber, a nozzle, a conduit for delivering'vapor from said casing to said nozzle,

aseeond nozzle in proximity to said first namedl nozzle, means for delivering entraining gas through said second nozzle, the two nozzles being disposed so that the entraining gas moving past the vapor nozzle; will entrain vapor emitted therefrom, means for delivering processing gas in the region of said nozzles, valve means for regufating the delivery of said processing gas, atubular member having a diverging chamber and an expansion chamber, the vapor, entraining gas and processing" gas flowing into these chambers, walls of said expansion chamber defining defleeting surfaces creating turbulence to intermix the vapor, entraining gas and processing gascompletely, burner means, a conduit from said expansion chamber to said burner means, a refractory shell surrounding said burner means, said shell having openings for delivering part of the heat of combustion developed at the burner means rearwardly toward said expansion chamber to heat the latter, the heatin of said expansion chamber and the turbulence created therein causing the intermixed vapor, entraining gas and processing gas therein to form a completely gasified combustible product which is delivered through said second conduit and emitted from said burner and burned in said shell, and electrical ignition means for starting combustion at the burner.

4. A device of the character described, comprising a member having a divergent chamber and an expansion chamber directly adjacent said divergent chamber, a burner, a conduit providing communication between said expansion chamber and said burner, a refractory shell surrounding said burner, a casing defining a fuel preheating chamber positioned between said refraotory shell and a wall of said expansion chamber, means for delivering liquidv fuel to said preheating chamber, means for heating. said preheating chamber to vaporize fuel delivered thereto, a nozzle, conduit means passing through said divergent and expansion chambers to connect said nozzle to said preheating chamber so that vapor emerges from the nozzle, a second nozzle in proximity to said first-named nozzle, means for delivering entraining gas through said second nozzle to entrain the vapor, means for delivering processing gas in the region ofsaid nozzles, valve means for controlling the delivery of said processing gas, the said gases and vapor flowing into said divergent chamber and then into: said expansion chamber, and becoming a gasified combustible product prior to emission at the burner, and means for igniting said combustible product.

5. A device of the character described, comprising a member having an expansion chamber, aburner, a refractory shell surrounding said burner, a casing defining a fuel preheating chamber positioned between said shell and said ex pansion chamber, means for delivering liquid fuel to said preheating chamber,v electrical means forv heating said preheating chamber to vaporize said liquid fuel, means for mixing the vaporized fuel with oxygen-containing gas and effecting gasification of the mixture in said expansion chamber to produce a gasified product, said burner communicating with said expansion chamber so that the gasified product is emitted therefrom, and means for igniting said gasified product upon emission from said burner, the burning of said gasified product taking place externa'lly of? said expansion chamber and within said refractory shell;

6. A device of the character described, comprising a member. having a divergent chamber and an expansion chamber directly adjacent said divergentchamber, a burner; a conduit connecting said burner means with said expansion chamber, a refractory shell surrounding said burner, a casing defining a fuel preheating chamber positioned between said refractory shell and a wall of said expansion chamber, means for delivering liquid fuel and oxygen-containing gas to said preheating chamber, means for heating said preheating chamber to vaporize fuel delivered thereto, a nozzle, conduit means passing through said divergent and expansion chambers for delivering vapor under pres ure from said preheating chamber to said nozzle, a second nozzle in proximity to said first-named nozzle, means for delivering entraining gas through said second nozzle to entrain the vapor emerging from said first-named nozzle, means for delivering processing gas in the region of said nozzles, and valve means for controlling the delivery of the processing gas, the said gases and vapor flowing into said divergent chamber and then into said expansion chamber prior to emission and burning at the burner.

'7. A device of the character described, comprising a member having an expansion chamber, a burner, a refractory shell surrounding said burner, a casing defining a fuel preheating chamber positioned between said shell and said expansion chamber, means for delivering liquid fuel to said preheating chamber, means for heating said preheating chamber to vaporize'said liquid fuel, and means for mixing the vaporized fuel with oxygen-containing gas and effecting complete gasification of the mixture in said expansion chamber to produce a gasifi'ed product, said burner communicating with said expansion chamber so that the gasified product is emitted from the burner and may be burned entirely externally of said expansion chamber and within said refractory shell,

8. A device of the character described comprising a member having an expansion chamber, a burner externall of said chamber, a refractory shell surrounding said burner, said shell having a wall with passages, a casing defining a fuel preheating chamber positioned between said shell and said expansion chamber, said shell being recessed to define a space between said casing and its said wall into which said passages open, an electric starting coil in said space in proximity to said passages, an electric heating coil in proximity to said: casing for preheating said casing and vaporizing fuel therein, and means for delivering liquid fuel to said preheating chamber for vaporization therein and means for mixing oxygen-containing gas with the vaporized fuel and means for effecting a substantially inseparable gaseous mixture of vaporized fuel and oxygen-containing gas in said expansion chamber, a conduit connectin said burner with said expansion chamber for delivering the substantially inseparable gaseous mixture from said expansion chamber for emission at said burner and for burning at said burner and externally of said expansion chamber and within said refractory shell.

9. That improvement in the process of combustion of liquid fuel comprising the steps of heating liquid fuel to vaporize it, delivering the vapor So formed under pressure to an entraining region, there entraining such vapor with oxygen-containing entraining gas, delivering oxygen-containing processing gas into the region of entrainment, then moving the gases and vapor as a primary stream through two expanding zones the first of which is divergent and the second of .which is abruptly larger in section than the largest section of, the divergent zone, impinging the said stream against a heated deflection surface in said second zone to deflect portions thereof along the surface of said second zone, redeflecting the deflected portions in said second zone to meet the primary stream entering said second zone thereby efiectin turbulence of the gases and vapor in said second zone and intermixing thereof to produce a homogeneous gasified combustible product, and thereafter burning the gasified combustible product in a zone separated from the two first-named zones.

10. That improvement in the process of combustion of liquid fuel comprising the steps of heating liquid fuel to vaporize it, delivering the vapor so formed under pressure to an entraining region, there 'entraining such vapor with oxygencontaining entraining gas, delivering oxygencontaining processing gas into the region of entrainment, then moving the gases and vapor as a primary stream through two expanding zones the first of which is divergent and the second of which is abruptly larger in section than the largest section of the divergent zone, impinging the said stream against a heated deflection surface in said second zone to deflect portions thereof along the surface of said second zone, redeflecting the deflected portions in said second zone to meet the primary stream entering said second zone there-by efiecting turbulence of the gases and vapor in said second zone and intermixing thereof to produce a homogeneous gasified combustible product, delivering the homogeneous gasified combustible product to a third zone separated from the second zone, burning the homogeneous gasifled combustible product in said third zone to provide hot products of combustion, and delivering part of the hot products of combustion to heat said deflection 14 chamber for vaporizing the fuel in said chamher, a nozzle, a conduit for delivering a mixture of fuel vapor and oxygen-containing gas from said chamber to said nozzle, a second nozzle in proximity to said first-named nozzle, means for delivering entraining gas through said second nozzle, said two nozzles being disposed so that the entrainin gas moving past the vapor nozzle will entrain the vapor and oxygen-containing gas emitted therefrom, means for delivering processing gas adjacent said nozzles, means for regulating the ratio of the volumes of the entraining gas and of the processing gas, a tubular member havin a diverging chamber and an expansion chamber into which said vapor and gases are delivered, walls of said expansion chamber defining deflecting surfaces for efiecting turbulence and intermixing of the vapor and ases delivered thereto, means for heating said expansion chamber s that the turbulent vapor and gases delivered thereto become a homogeneous gasified combustible product, and means for burning such gasified combustible product externally of said expansion chamber.

RICHARD J. WALLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,102,984 Gleich July 7, 1914 1,849,876 Doble Aug. 17, 1920 1,574,545 Bear Feb. 23, 1926 1,631,662 Weydell June 7, 1927 1,676,501 Moors July 10, 1928 1,700,269 Loepsinger Jan. 29, 1929 1,860,958 Sallee May 31, 1932 2,069,960 La Pointe Feb. 9, 1937 2,136,727 Pirich Nov. 15, 1938 2,157,265 Pothier et al. May 9, 1939 2,175,866 Arnold Oct. 10, 1939 2,194,599 Katz Mar. 26, 1940 2,286,853 Holthouse June 16, 1942 2,384,836 Holthouse Sept. 18, 1945 2,443,707 Korsgren June 2, 1948 FOREIGN PATENTS Number Country Date 577,032 France Feb. 11, 1924 

